The present Invention relates to an electrical junction box for use in a motor vehicle and, more particularly, to reinforcing the area around the opening in the outer box, through which the wires pass while stabilizing the electrical unit contained therein.
Electrical junction boxes used in automobiles employ an outer box in which an electrical unit is housed. Typically, these electrical junction boxes are found in the engine compartment of a motor vehicle. The primary purpose of the outer box is to protect the electrical connection or electrical unit from dust and water. Conventionally, the outer box comprises an upper cover and a lower cover which fit around and house the electrical unit. Typically, the upper and lower covers of the outer box are made by molding resins or plastic. The outer box is often referred to as an auxiliary box while examples of electrical units, housed in the auxiliary box, include junction blocks, relay blocks, and fuse blocks.
In order to connect the electrical unit to the other electrical/mechanical parts of the vehicle, openings are generally molded into the lower cover of the outer box. These openings allow wires to pass into and out of the box.
FIGS. 1 and 2 illustrate a conventional electrical junction box arrangement used in a vehicle. Lower cover 1 has notch 1a disposed in its side wall. Typically, notch 1a is formed during the molding process and starts near the bottom surface of lower cover 1 and extends the complete length of the side wall as shown. Ledge 1b is disposed horizontally on the inner wall of lower cover 1 and typically extends around the complete inner perimeter surface thereof.
In order to assemble the electrical junction box, electrical unit 2, depicted as a relay block, is lowered into lower cover 1 through opening 1c until the bottom surface of electrical unit 2 rests on ledge 1b, as shown in FIG. 2. Wires are connected to electrical unit 2 and aligned with notch 1a; upper cover 3 is then placed on lower cover 1 and electrical unit 2 to complete the assembly.
A problem exists with the prior art arrangement in that, when notch 1a is large, the area around notch 1a in the side wall of lower cover 1 is weak. This is especially true if lower cover 1 has a plurality of notches. The overall strength of lower cover 1 may be insufficient to withstand the rigors of an automobile assembly plant or the life of the vehicle on the road. Decreasing the size of notch 1a is not a viable solution because it makes assembly difficult due to the number of wires that are connected to electrical unit 2.
Additionally, because electrical unit 2 merely rests on projection 1b, it is not securely held in the outer box and, vibrations due to the automobile traveling over the road, shake electrical unit 2 and can cause a weakening of the electrical connection between electrical unit 2 and the wires. The vibrations can also cause electrical unit 2 to shake inside the outer box and result in a noise which is annoying to the driver or passengers in the vehicle and result in the impression that something is wrong.
Furthermore, ledge 1b is usually positioned so that a portion of electrical unit 2 extends above the top of lower cover 1. This requires that the side wall of lower cover 1 meet the side wall of upper cover 3 in order to form a good dust proof and watertight seal.